/*
 * Copyright 2009-2013 by The Regents of the University of California
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * you may obtain a copy of the License from
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.uci.ics.hyracks.dataflow.common.data.parsers;

import java.io.DataOutput;
import java.io.IOException;

import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;

public class LongParserFactory implements IValueParserFactory {
    public static final IValueParserFactory INSTANCE = new LongParserFactory();

    private static final long serialVersionUID = 1L;

    private LongParserFactory() {
    }

    @Override
    public IValueParser createValueParser() {
        return new IValueParser() {
            @Override
            public void parse(char[] buffer, int start, int length, DataOutput out) throws HyracksDataException {
                long n = 0;
                int sign = 1;
                int i = 0;
                boolean pre = true;
                for (; pre && i < length; ++i) {
                    char ch = buffer[i + start];
                    switch (ch) {
                        case ' ':
                        case '\t':
                        case '\n':
                        case '\r':
                        case '\f':
                            break;

                        case '-':
                            sign = -1;
                            pre = false;
                            break;

                        case '0':
                        case '1':
                        case '2':
                        case '3':
                        case '4':
                        case '5':
                        case '6':
                        case '7':
                        case '8':
                        case '9':
                            pre = false;
                            n = n * 10 + (ch - '0');
                            break;

                        default:
                            throw new HyracksDataException("Encountered " + ch);
                    }
                }
                boolean post = false;
                for (; !post && i < length; ++i) {
                    char ch = buffer[i + start];
                    switch (ch) {
                        case '0':
                        case '1':
                        case '2':
                        case '3':
                        case '4':
                        case '5':
                        case '6':
                        case '7':
                        case '8':
                        case '9':
                            n = n * 10 + (ch - '0');
                            break;
                    }
                }

                for (; i < length; ++i) {
                    char ch = buffer[i + start];
                    switch (ch) {
                        case ' ':
                        case '\t':
                        case '\n':
                        case '\r':
                        case '\f':
                            break;

                        default:
                            throw new HyracksDataException("Encountered " + ch);
                    }
                }
                
                try {
                    out.writeLong(n * sign);
                } catch (IOException e) {
                    throw new HyracksDataException(e);
                }
            }
        };
    }
}